1. Field of the Invention
The present invention relates to a data driver and an organic light emitting display device including the same, and more particularly, to a data driver and an organic light emitting display device including the same, in which an image is displayed with desired brightness.
2. Discussion of Related Art
Various flat panel displays have recently been developed as alternatives to a relatively heavy and bulky cathode ray tube (CRT) display device. The flat panel display devices include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), organic light emitting diode (OLED) displays, etc.
Among the flat panel display devices, the organic light emitting diode display device can emit light by electron-hole recombination. Such an organic light emitting diode display device has advantages of relatively fast response time and relatively low power consumption. Typically, the organic light emitting diode display device employs a transistor provided in each pixel for supplying current corresponding to a data signal to an organic light emitting diode, thereby enabling the organic light emitting diode to emit light.
FIG. 1 illustrates a conventional organic light emitting diode display device.
Referring to FIG. 1, a conventional organic light emitting diode display device includes a display region 30 including pixels 40 formed in a region defined by intersection of scan lines S1 through Sn and data lines D1 through Dm; a scan driver 10 to drive the scan lines S1 through Sn; a data driving part 20 to drive the data lines D1 through Dm; and a timing controller 50 to control the scan driver 10 and the data driving part 20. Each pixel 40 includes a transistor for supplying current to a light emitting device (not shown).
The timing controller 50 generates a data control signal DCS and a scan control signal SCS corresponding to an external synchronization signal. The data control signal DCS and the scan control signal SCS are supplied from the timing controller 50 to the data driving part 20 and the scan driver 10, respectively. Further, the timing controller 50 supplies external data to the data driving part 20.
The scan driver 10 receives the scan control signal SCS from the timing controller 50. The scan driver 10 generates scan signals on the basis of the scan control signal SCS and supplies the scan signals to the scan lines S1 through Sn.
The data driving part 20 receives the data control signal DCS from the timing controller 50. The data driving part 20 generates data signals on the basis of the data control signal DCS and supplies the data signals to the data lines D1 through Dm in synchronization with the scan signals.
The display portion 30 receives a first voltage ELVDD and a second voltage ELVSS from an external power source, and supplies them to the pixels 40. When the first voltage ELVDD and the second voltage ELVSS are applied to the pixels 40, each pixel 40 controls a current corresponding to the data signal to flow from a first power source line supplying the first voltage ELVDD to a second power source line supplying the second voltage ELVSS via an organic light emitting diode, thereby emitting light corresponding to the data signal.
Therefore, in the conventional organic light emitting diode display device, each pixel 40 emits light with a predetermined brightness corresponding to the data signal. However, the pixels 40 do not generally emit light with a desired brightness because the transistors provided in the respective pixels 40 have different threshold voltages. Further, in the conventional organic light emitting diode display device, there is no method of measuring and controlling a real current in each pixel 40 corresponding to the data signal.